Pore formation domain of human pro-apoptotic Bax induces mammalian apoptosis as well as bacterial death without antagonizing anti-apoptotic factors.
A trace amount of the pro-apoptotic factor human Bax was sufficient to kill host Escherichia coli (Asoh, S., Nishimaki, K., Nanbu-Wakao, R., and Ohta, S., submitted). The region of Bax lethal to E. coli cells was determined by introducing truncated human bax mutant genes. A peptide corresponding to amino acid residues 115 to 144 of Bax was the smallest peptide capable of inducing cell death of E. coli. A truncated bax gene (Bax112-192) containing the region lethal to E. coli was then introduced into a murine promyeloid cell line, FDC-P1. Constitutively expressed Bax112-192 induced apoptosis as judged by decrease of transfectants surviving and DNA fragmentation. These results indicate that Bax112-192 contains the region directly responsible for mammalian apoptosis as well as bacterial death. Flow cytometric analysis by FITC-Annexin V showed that the transfectant cells expressing Bax112-192 or native Bax became apoptotic even without external stimuli. The apoptotic population in the cells expressing Bax112-192 was not decreased by co-expression of Bcl-2 or Bcl-XL, while Bcl-2 or Bcl-XL suppressed apoptosis in the cells expressing native Bax. Therefore, Bax induces apoptosis by its own activity without blocking the anti-apoptotic activity involved in Bcl-2 or Bcl-XL.
Ishibashi
Y
Y
Department of Biochemistry and Cell Biology, Nippon Medical School, Kanagawa, Japan.
Nishimaki
K
K
Asoh
S
S
Nanbu-Wakao
R
R
Yamada
T
T
Ohta
S
S
D017209:Apoptosis / Q000235:genetics* / Q000502:physiology; D002470:Cell Survival / Q000235:genetics; D003001:Cloning, Molecular; D053938:DNA Fragmentation / Q000235:genetics; D004926:Escherichia coli / Q000502:physiology; D005786:Gene Expression Regulation / Q000235:genetics; D019254:Genes, bcl-2 / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D017384:Sequence Deletion / Q000235:genetics; D014162:Transfection / Q000235:genetics; D014407:Tumor Cells, Cultured; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
C494826:BAX protein, human; C494811:BCL2L1 protein, human; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein